Department of Chemistry, Shiraz University, Shiraz, Iran.
Inorg Chem. 2012 Mar 19;51(6):3454-64. doi: 10.1021/ic202141g. Epub 2012 Feb 24.
The interactions of two organoplatinum complexes, [Pt(C^N)Cl(dppa)], 1, and [Pt(C^N)Cl(dppm)], 2 (C^N = N(1), C(2')-chelated, deprotonated 2-phenylpyridine, dppa = bis(diphenylphosphino)amine, dppm = bis(diphenylphosphino)methane), as antitumor agents, with bovine serum albumin (BSA) and human serum albumin (HSA) have been studied by fluorescence and UV-vis absorption spectroscopic techniques at pH 7.40. The quenching constants and binding parameters (binding constants and number of binding sites) were determined by fluorescence quenching method. The obtained results revealed that there is a strong binding interaction between the ligands and proteins. The calculated thermodynamic parameters (ΔG, ΔH, and ΔS) confirmed that the binding reaction is mainly entropy-driven, and hydrophobic forces played a major role in the reaction. The displacement experiment shows that these Pt complexes can bind to the subdomain IIA (site I) of albumin. Moreover, synchronous fluorescence spectroscopy studies revealed some changes in the local polarity around the tryptophan residues. Finally, the distance, r, between donor (serum albumin) and acceptor (Pt complexes) was obtained according to Förster theory of nonradiation energy transfer.
两种有机铂配合物[Pt(C^N)Cl(dppa)]，1 和 [Pt(C^N)Cl(dppm)]，2（C^N = N(1)，C(2')-螯合，去质子化 2-苯基吡啶，dppa = 双（二苯基膦）胺，dppm = 双（二苯基膦基）甲烷）作为抗肿瘤剂，与人血清白蛋白（HSA）和牛血清白蛋白（BSA）的相互作用已通过荧光和紫外可见吸收光谱技术在 pH 7.40 下进行了研究。通过荧光猝灭法确定了猝灭常数和结合参数（结合常数和结合位点数）。所得结果表明，配体与蛋白质之间存在强烈的结合相互作用。计算得到的热力学参数（ΔG、ΔH 和 ΔS）证实，结合反应主要是熵驱动的，疏水作用力在反应中起主要作用。置换实验表明，这些 Pt 配合物可以与白蛋白的亚域 IIA（位点 I）结合。此外，同步荧光光谱研究揭示了色氨酸残基周围局部极性的一些变化。最后，根据福斯特非辐射能量转移理论，获得了供体（血清白蛋白）和受体（Pt 配合物）之间的距离 r。
